(1) Field of the Invention
This invention relates to a microwave circuit device, and more particularly to a circuit device in which a microwave integrated circuit is installed within a microwave waveguide device including a rectangular waveguide, a horn antenna, etc.
(2) Description of the Prior Art
As a device for measuring a velocity or for detecting an obstacle and carried on an automobile, there has been considered the Doppler radar which makes use of microwaves.
Such a device requires a rectangular waveguide, a horn antenna etc. for transmitting and receiving the microwaves. In order to miniaturize the device, a circuit for the transmission and reception put into the form of a microwave integrated circuit is assembled in the waveguide.
In devices such as the radar which radiate the microwaves, the transmission power needs to be kept at a very low level (below 1 .mu.W) in view of influences on other wireless equipment. On the other hand, the receiving sensitivity needs to be made as high as possible.
Further, in the actual installation, this type of device requires the control of leaky electric power or the reduction of noise generated in a local oscillator and appearing in a signal output.